Criterion is the singular form of criteria.
The word 'criteria' is the plural form of the singular word 'criterion'. 'Those are the criteria that I used in making my decision.' 'That is the criterion that I used in making my decision.' It is wrong to use the word 'criteria' as a singular. Similarly, it is wrong to use 'phenomena' as a singular. It is the plural form of the singular word 'phenomenon'.
Criteria is plural. The singular form is criterion.
The word 'duo' is the singular form; the plural form is duos.
The singular form of the word "señores" is "señor."
The singular form of Sioux is "Sioux." It is both the singular and plural form of the word.
The word 'criteria' is the plural form of the singular word 'criterion'. 'Those are the criteria that I used in making my decision.' 'That is the criterion that I used in making my decision.' It is wrong to use the word 'criteria' as a singular. Similarly, it is wrong to use 'phenomena' as a singular. It is the plural form of the singular word 'phenomenon'.
I take it you mean 'What is the singular form of the word criteria?' If so, the answer is criterion.
Criteria is plural. The singular form is criterion.
Criteria is plural. Criterion is singular. The criteria to pass a maths exam is being able to add up and subtract. The criterion of passing an addition exam is being able to add up.
Criterion is the singular form.
Criterion
Criterion is singular. The word criteria is actually the plural.
The singular form of the word flagella is flagellum.
The word 'duo' is the singular form; the plural form is duos.
Criteria is a plural. The singular is criterion, of which the possessive is criterion's. The PLURAL possessive is criteria's.
The singular form of the word "señores" is "señor."
That is the singular form; the plural form is those.